1. Field of the Invention
The present invention relates to an image processing system and a control method for the system, a photographing system and a control method for the system, and a computer-readable memory, which process an image signal obtained by electronically converting an image input and output the processed signal.
2. Description of the Related Art
In a conventional scheme used to obtain a medical X-ray radiographic image for a long time, the distribution of X-rays transmitted through a human body is converted into a fluorescence distribution of a phosphor, the light intensity is directly printed on a film, and the film is developed. In recent years, a radiographic image is read out as an electrical signal using a scheme of forming a latent image of an X-ray intensity distribution as an energy on a photostimulable phosphor and reading out the image, a scheme of directly reading the fluorescence distribution of a phosphor by X-rays as an image, or a technique without use of a fluorescence distribution. The electrical signal is converted into digital data to form a digital image. Use of digital images allows efficient filing, practical use of remote diagnosis, and improvement of the diagnostic technology and efficiency. In addition, digital images make various image processing operations possible and are also changing the diagnosis method.
Under these circumstances, as disclosed in Japanese Patent Laid-Open No. 09-098970 proposed by the present applicant, an X-ray image sensing apparatus using a wide-screen two-dimensional solid-state image sensing device has been provided. An X-ray detection apparatus capable of detecting an X-ray radiographic image larger than a conventional regular size film can be manufactured.
Generally, a film used to photograph an X-ray image of a thoracic or abdominal portion has a half size (14″×17″) or a large size (14″×14″). As for the direction of a film in photographing, a film with half size is generally set long in the vertical direction (so-called portrait). Sometimes, an image to be photographed does not completely fall within the film area depending on the height or form of the person to be examined. When the image to be photographed stretches out in the vertical direction, the person to be examined must vertically move to acquire a photographed image. In this case, X-rays are radiated twice to acquire a photographed image, resulting in an increase in X-ray dose for the person to be examined. When the image to be photographed stretches out in the horizontal direction, the person to be examined must move in the horizontal direction to photograph the image twice. Alternatively, a horizontally elongated film (so-called landscape) as shown in FIG. 3 is used to acquire a photographed image. When the to-be-photographed image of the person to be examined does not fall within the film area, the X-ray dose for the person to be examined increases. Additionally, the operation becomes cumbersome because, e.g., the direction of the X-ray detection apparatus need be changed from portrait to landscape.
The sensor area of a digital X-ray sensing apparatus may be larger than a film screen system. For example, the CXDI (trademark) available from Canon has a size of 17″ (43 cm)×17″ (43 cm). Commercially available films have only predetermined sizes: 14″×17″, 14″×14″, or 10″×12″. Hence, to print an image on a commercially available film, the area to be extracted from a 17″×17″ image, and the film to be used must be carefully selected.
On the other hand, for many commercially available image viewers, allowable image sizes are predetermined. Especially, the maximum size is often predetermined. For commercially available diagnostic viewers, the maximum allowable size of an image is 2,048×2,048 pixels. Hence, even when an image is to be output to a medium other than a film, the same problem as for a film is posed.